According to the published literature, solid dosage forms made from sodium ibuprofen are superior in pharmaceutical kinetics (i.e., they enter and peak in the blood stream more rapidly than other solid dosage forms of ibuprofen). However, despite intensive research in the field, it remains difficult to form solid dosage forms from sodium ibuprofen using conventional approaches. One of the difficulties is that sodium ibuprofen dihydrate has poor flowability characteristics and thus tends to cake readily even when blended with conventional anti-caking agents such as colloidal silica or talc. The poor flow characteristics of sodium ibuprofen dihydrate, even though formulated with flow improvers, can result in erratic weight variations in the solid dosage forms such as tablets and caplets being produced. Another difficulty in forming sodium ibuprofen tablets and caplets is the tendency of sodium ibuprofen dihydrate to form film coatings on the punch surfaces of the rotary press. Such film coatings, when not excessive, are nonetheless undesirable because they reduce the shininess or gloss of the tablets or caplets being formed. If excessive coatings are formed on the punch surfaces, several operational difficulties are encountered. First of all, defects in the tablets or caplets being formed will occur. Secondly, erratic punch operation results. And thirdly, unacceptable variations in tablet or caplet weights can also be experienced. Any of these operational difficulties in turn will result in the need to shut down the equipment in order to clean the punch surfaces.
It would therefore be of considerable advantage if a way could be found of forming sodium ibuprofen compositions capable of being more readily converted into solid dosage form such as tablets or caplets using conventional rotary press tableting equipment without encountering the various difficulties referred to above. It would also be of considerable advantage if a way could be found of producing highly flowable granules from sodium ibuprofen dihydrate so that the dosage level of hard shell capsules filled with the granules can be kept more uniform.
This invention addresses all of the foregoing needs in an effective manner.